Long-term weight loss and changes in blood pressure: Results of the trials of hypertension prevention, phase II

Background: Weight loss appears to be an effective method for primary prevention of hypertension. However, the long-term effects of weight loss on blood pressure have not been extensively studied. Objective: To present detailed results from the weight loss arm of Trials of Hypertension Prevention (TOHP) II. Design: Multicenter, randomized clinical trial testing the efficacy of lifestyle interventions for reducing blood pressure over 3 to 4 years. Participants in TOHP II were randomly assigned to one of four groups. This report focuses only on participants assigned to the weight loss (n = 595) and usual care control (n = 596) groups. Patients: Men and women 30 to 54 years of age who had nonmedicated diastolic blood pressure of 83 to 89 mm Hg and systolic blood pressure less than 140 mm Hg and were 110% to 165% of their ideal body weight at baseline. Intervention: The weight loss intervention included a 3-year program of group meetings and individual counseling focused on dietary change, physical activity, and social support. Measurements: Weight and blood pressure data were collected every 6 months by staff who were blinded to treatment assignment. Results: Mean weight change from baseline in the intervention group was -4.4 kg at 6 months, -2.0 kg at 18 months, and -0.2 kg at 36 months. Mean weight change in the control group at the same time points was 0.1, 0.7, and 1.8 kg. Blood pressure was significantly lower in the intervention group than in the control group at 6, 18, and 36 months. The risk ratio for hypertension in the intervention group was 0.58 (95% Cl, 0.36 to 0.94) at 6 months, 0.78 (Cl, 0.62 to 1.00) at 18 months, and 0.81 (Cl, 0.70 to 0.95) at 36 months. In subgroup analyses, intervention participants who lost at least 4.5 kg at 6 months and maintained this weight reduction for the next 30 months had the greatest reduction in blood pressure and a relative risk for hypertension of 0.35 (Cl, 0.20 to 0.59). Conclusions: Clinically significant long-term reductions in blood pressure and reduced risk for hypertension can be achieved with even modest weight loss.